JP6588149B2 - Fuel feed pump - Google Patents

Description

  The present invention is a fuel feed pump that pumps fuel, and includes an electric motor and a pump impeller that can be driven by the electric motor. The pump impeller has a rotational movement of a rotor that is connected to the pump impeller via a shaft. The shaft is coupled to the rotor of the electric motor by means of a shaft, which is axially directed by a thrust bearing and / or radially by a radial bearing relative to the pump stage in which the pump impeller is arranged. Relates to a fuel feed pump.

  A fuel to be pumped not only flows through the fuel feed pump but also flows around it. A fuel feed pump used in an automobile has, for example, an electric motor used to drive a pressure feed stage formed by a pump impeller. In order to ensure safety against electrostatic discharge (ESD), it is necessary to ground the conductive member of the fuel feed pump. This helps to prevent a short circuit and thus a spark that can lead to fuel ignition. Furthermore, the functionality of the fuel feed pump can be impaired by the occurrence of electrostatic discharge. The members to be grounded include in particular the pump stage, the fuel feed pump housing, and the motor housing in which the rotor and stator of the electric motor are arranged.

  At the same time, it should be avoided to short-circuit the shaft of the fuel feed pump in which the pumping stage is arranged to the negative electrode of the voltage supply unit or to the ground potential, and thus to ground in the same way. Such a short circuit can lead to fuel feed pump failure or the generation of undesirable deposits in the shaft or rotor, particularly near the carbon brush. This can adversely affect the life of the fuel feed pump.

  A variety of devices are known in the prior art that represent possible solutions to such problems. Therefore, fuel feed pumps with additional resistance are known to achieve sufficient grounding or shut-off. Fuel feed pumps having a pump stage made of plastic are also known, whereby shaft insulation can be achieved. Furthermore, fuel feed pumps are known that ground the motor housing and thus the shaft.

  The disadvantages of such devices of the prior art are that, in particular, sufficient safety against electrostatic discharge cannot be obtained, or grounding of the motor housing can also cause shaft grounding, thereby creating deposits within the electric motor. That is. When the pump step portion is configured as a plastic member, the stability is lowered and the life is shortened.

DESCRIPTION OF THE INVENTION, PROBLEMS, SOLUTIONS AND ADVANTAGES Accordingly, it is an object of the present invention to provide a fuel feed pump that has sufficient safety against electrostatic discharge and at the same time has an electrical disconnection of the shaft to the grounded member. Is to provide.

  This problem concerning the fuel feed pump is solved by a fuel feed pump having the features of claim 1.

  An embodiment of the present invention is a fuel feed pump that pumps fuel, and includes an electric motor and a pump impeller that can be driven by the electric motor, and the pump impeller pumps a rotary motion of a rotor via a shaft. The shaft is coupled to the rotor of the electric motor by a shaft so that it is transmitted to the impeller, the shaft being axially and / or radially bearing by a thrust bearing relative to the pump stage where the pump impeller is arranged The electric insulation member is arranged between the thrust bearing and the pump stage, and / or the electric insulation member is arranged between the radial bearing and the pump stage. The fuel feed pump.

  The electrical insulation of the shaft from the pump stage, and thus the housing of the fuel feed pump, by arranging an electrical insulation between the thrust bearing and the pump stage and / or between the radial bearing and the pump stage And electrical isolation from the motor housing. This is particularly advantageous to avoid the formation of deposits in the shaft region based on the polarity of the shaft. By electrical insulation, the housing of the fuel feed pump, the motor housing and the pump stage can be connected to the negative electrode of the voltage supply or to ground potential, and thus the above-mentioned grounding of the member can be achieved. This is advantageous to avoid short circuits and electrostatic discharges.

  The motor housing may be formed by a stator of an electric motor, for example. Similarly, a cage-like structure that functions as a motor housing may be disposed around the stator. By fitting the electric motor within the housing of the fuel feed pump, the electric motor is well protected from the effects of mechanical failure without a closed, inherent housing.

  It is preferable to dispose an electrical insulating member not only between the radial bearing and the pump stage but also between the thrust bearing and the pump stage. Thereby, a wide range of electrical insulation of the shaft can be achieved.

  It is particularly advantageous if the radial bearing is formed as an electrically insulating member. In order to save additional insulation members, radial bearings can also have an electrical insulation function in addition to the bearing function. For this purpose, the radial bearing may be formed from a non-conductive material, particularly preferably. For example, the bearing shell may be formed from plastic or non-conductive ceramic. The radial bearing may be covered with a non-conductive coating.

  It is also advantageous if the electrically insulating member between the thrust bearing and the pump stage is formed by a topffoermig member. The pan-shaped member is advantageous in order to ensure a reliable fitting of the thrust bearing and to allow easy installation of the insulating member. For this purpose, a recess that can be fitted or press-fitted with an insulating member and that provides an accurate fit may be provided in the lower part of the pump step.

  The pump stage is preferably formed by a two-part housing that forms the lower end of the fuel feed pump housing. A pump impeller is disposed in the pump step. Furthermore, the pump stage has an additional opening for sucking and discharging the fluid to be pumped.

  It is also preferable that the thrust bearing is formed of a sphere, and the sphere is disposed in the pan-like electrical insulating member. The sphere is advantageous because the shaft can be supported and supported in the axial direction and there is only a very small contact surface between the shaft and the sphere. The sphere can be press-fitted into the recess of the pump step where the insulating member is already fitted, so that the sphere is preferably tightly accommodated in the pump step. Alternatively, it can be expected that the sphere slides on the insulating member, so that the thrust bearing is finally formed either by the sphere or by the pan-like insulating member.

  Furthermore, it is advantageous if the electrically insulating member is formed by a non-conductive coating. A non-conductive coating of the pump stage in the area of thrust and / or radial bearings is advantageous because it can also achieve electrical insulation as well. The coating is preferably made of a non-conductive material such as plastic or ceramic.

  Furthermore, it is advantageous if at least one of the electrically insulating members is made of plastic and / or ceramic. In this case, it is particularly advantageous if at least one of the electrically insulating members is made of a thermoplastic material.

  Furthermore, it is advantageous if a non-conductive sealing member is arranged between the shaft and the pump stage. The seal member may be a ceramic or rubber member, for example.

  Advantageous refinements of the invention are described in the dependent claims and in the following description of the drawings.

  Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings.

It is the schematic which shows arrangement | positioning of the fuel feed pump in a fuel tank. It is detail drawing of the lower part of a pump step part, and especially the pan-shaped insulation member and the spherical body which acts as a thrust bearing are shown. FIG. 3 is a cross-sectional view of a fuel feed pump, wherein a non-conductive radial bearing is disposed between the shaft and the pump step, and the non-conductive pan-shaped insulating member is a shaft directed downward of the shaft. It is arranged between the directional end region and the pump stage.

  FIG. 1 shows a schematic view of a fuel tank 1 provided in an automobile (not shown). A fuel feed unit 2 is disposed in the fuel tank 1, and the fuel feed unit 2 includes a swirl pot 3, a fuel feed pump 4, and a flange 5. The flange 5 is used to attach the fuel feed unit 2 to the fuel tank 1. The swirl pot 3 is a fuel reservoir, from which fuel is pumped to the internal combustion engine by the fuel feed pump 4. The swirl pot 3 is coupled to the flange 5 via a coupling member 6. Further, the swirl pot 3 is supported against the lower wall of the fuel tank 1.

  The fuel feed pump 4 is disposed inside the swirl pot 3 and is connected to a voltage source via a conductor 7. Both the fuel feed pump 4 and the conductor 7 are surrounded by the fuel in the fuel tank 1. Therefore, it is necessary to ground the metal member that is in contact with the fuel to ensure safe operation.

  FIG. 2 shows a detailed view of the lower part 10 of the pump step 11. The pump step portion 11 is usually composed of two parts, and has a recess for accommodating the pump impeller therein. Furthermore, the pump stage 11 has an additional opening through which fuel can be pumped to and from the pump stage 11.

  The part 10 has a sphere 12, which is used as an axial bearing seat for a shaft (not shown in FIG. 2) disposed above it. The sphere 12 is preferably manufactured from an abrasion resistant material. The sphere 12 is preferably formed from a metal material. The spherical body 12 is disposed in the pan-shaped member 13, and the spherical body 12 is separated from the portion 10 by the pan-shaped member 13. The pan-shaped member 13 is preferably made of a non-conductive material. In particular, the electrical connection between the sphere 12 and a shaft (not shown) that is conductively connected to the sphere 12 and on which a pump impeller is disposed. Help with insulation. Accordingly, the pan-like member 13 constitutes an electrical insulating member.

  FIG. 3 shows a cross-sectional view of the fuel feed pump 15. A shaft 16 is disposed in the center of the fuel feed pump 15, and this shaft 16 is coupled to the rotor 17 of the electric motor 18 and is rotatably supported in the housing 19 of the fuel feed pump 15. Yes.

  The shaft 16 is supported on the one hand by a radial bearing 20 and on the other hand by a thrust bearing formed by the sphere 12 already shown in FIG.

  In particular, the housing 19, the pump stage 11 and the stator 22 of the fuel feed pump 15 are connected to the negative electrode of the voltage supply, or in particular to the ground potential, in order to ensure the grounding of the members.

  The radial bearing 20 is incorporated in the upper part 21 of the pump step 11 and is preferably made of an electrically insulating material. In this way, the conductive connection between the shaft 16 and the pump stage 11 is prevented. Alternatively, an electrical insulating layer or an electrical insulating member may be disposed between the radial bearing 20 and the pump step portion 11 or the upper portion 21.

  A non-conductive radial bearing 20 or a combination of an insulating member between the radial bearing 20 and the pump stage 11 and a pan-like member 13 made of an electrically insulating material can be used for a grounded member of the fuel feed pump 15. Electrical insulation of the shaft 16 is achieved. This prevents the generation of deposits on the shaft 16, especially in the region of the carbon brush 23 of the electric motor 18, thereby improving the overall life of the fuel feed pump 15.

  The embodiment shown in FIGS. 1 to 3 does not have a particularly limited feature and serves to clarify the idea of the present invention. Various shapes and shapes different from the above can be realized without departing from the basic idea of the present invention within the scope of the present invention. The embodiments shown in FIGS. 2 and 3 are exemplary and adversely affect the life of the fuel feed pump by selecting an inappropriate material, such as using plastic for the housing and / or pump stage. It clearly demonstrates the particularly advantageous possibility of achieving insulation of the shaft from the electrically grounded part of the fuel feed pump without the shaft.

Claims (7)

A fuel feed pump (4, 15) for pumping fuel,
An electric motor (18) and a pump impeller that can be driven by the electric motor (18) are provided. The pump impeller is configured such that the rotational movement of the rotor (17) is transmitted through the shaft (16). The shaft (16) is coupled to the rotor (17) of the electric motor (18) so as to be transmitted to the vehicle, and the shaft (16) is a pump stage where the pump impeller is disposed. (11) in the fuel feed pump (4, 15), supported axially by a thrust bearing (12) and / or radially by a radial bearing (20),
An electrical insulating member (13) is disposed between the thrust bearing (12) and the pump stage (11), and / or the radial bearing (20) and the pump stage (11) In between, an electrical insulation member is arranged ,
The electrical insulating member (13) is formed by a pan-like member (13) between the thrust bearing (12) and the pump step (11).
A fuel feed pump (4, 15), characterized in that   The fuel feed pump (4, 15) according to claim 1, wherein the radial bearing (20) is configured as an electrically insulating member. The thrust bearing (12) is formed by a spherical body (12), the sphere (12), the are arranged in a pot-shaped member (13) in claim 1 or 2 fuel feed pump according (4, 15). The fuel feed pump (4, 15) according to any one of claims 1 to 3 , wherein the electrically insulating member (13) is formed by a non-conductive coating. The fuel feed pump (4, 15) according to any one of claims 1 to 4 , wherein at least one of the electrically insulating members (13) is made of plastic and / or ceramic. Wherein at least one of the electrically insulating member (13, 20) is formed from a thermoplastic material, any one of claims fuel feed pump of claims 1 to 5 (4, 15). The fuel feed pump (4, 15) according to any one of claims 1 to 6 , wherein a non-conductive sealing member is arranged between the shaft (16) and the pump step (11). ).

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